US 3700405 A
Description (OCR text may contain errors)
Int. Cl. D06p /04 US. Cl. 8-173 6 Claims ABSTRACT OF THE DISCLOSURE Processes are provided for the dyeing of silk-like linear, high molecular weight polyamide fibers containing at least 90% repeating units of the formula wherein R is the same or different member of the class consisting of hydrogen and methyl with selected anionic dyestuffs under acidic conditions and temperatures of between about 180 to 212 F. By use of selected organic carriers, the use of pressure is not required.
The present invention relates to processes for dyeing polyamide fibers containing at least 90% of the repeating units of the formula wherein R is the same or different member of the class consisting of hydrogen and methyl. At least 40% by weight of the diamino constituent of the repeating units is of the trans, trans stereoisomeric configuration.
The manufacture of these fibers as well as the abovediscussed structure is detailed in US. Pat. 3,393,210 to Speck, which specification is incorporated by reference herein. a
As exemplary of these materials is the polyamide polycondensate of 4,4'- diamino-dicyclohexylmethane with dodecanedioic acid. Such material is commercially avail able from Du Pont in different grades, depending on finish, denier, etc., as nylon types 472 and 473, as well as Qiana. The latter materials have a silk-like handle, a density of 1.04 and a crystallinity similar to that of polyester fibers, as reported in an article entitled The Dyeing of Synthetic Polymer Fibers, A. Liddiard, appearing in Review of Progress in Coloration, vol. 1, p. 64, June l967-September 1969.
US. Pat. No. 3,393,210, mentioned above, further discloses that the polyamide fibers are dyed under pressure in the presence of carriers customarily used for polyester fibers at temperatures between 115 and 120 C. This behavior is rather atypical of polyamides since polyamides such as nylon 6 or 66 are readily dyed in the absence of carriers. This difficult dyeability is attributed to the relatively few and relatively inaccessible free amino groups on the fiber. It was, therefore, an object of the present inventors to achieve dyeings at atmospheric pressure and at temperatures up to about the boiling point of the aqueous dye solution, e.g. about 212 F.
The Liddiard article, discussed above, does disclose that the Du Pont type 472 polyamides may be dyed with disperse dyes at the boil in the presence of a carrier, or in the absence of a carrier at even higher temperatures.
; United States Patent 0 Since disperse dyes do not give a very satisfactory heat sublimation light or wash resistance, it was a further object of the present inventors to find a method for dyeing type 472 nylon fibers with traditionally fast classes of dyestuffs.
The above-discussed objectives could not be attained by the use of conventional polyamide, e.g. nylon-6 or 66 formulations since these methods gave little or no dye exhaustion.
The above objectives were finally realized by the use of a carefully controlled combination of pH, temperature, dyestuif and carrier.
With respect to carriers, the most preferred is benzophenone, however, this may be employed and mixed with other carriers such as butyl benzoate, especially in a 1:1 mixture. Other operable carriers include benzyl benzoate, phenyl benzoate, o-bromo benzoic acid, 2-chloro benzoic acid, mono benzyl phthalate, o-anisaldehyde, benzoin, succinic acid and toluic acid. Such carriers may be employed alone or in admixture with each other as well as with benzophenone and/or butyl benzoate. Normally, 10 to 25 weight percent of carrier, based on the weight of the fiber to be treated, produces satisfactory results.
With respect to temperatures of dyeing, about 180 F. up to about the boiling point of the aqueous dyebath, e.g., about 212 F., may be employed with temperatures in the range of 200 to 212 F. being preferred.
Control of pH is very important and a pH range of between 2 and 5 must be employed to insure substantial dyebath exhaustion. Conventional acids used in dyebath formulations, e.g., formic, acetic, sulphuric or phosphoric acid are preferably employed. Formic acid is most preferred because it offers the highest degree of exhaustion.
With respect to dyestuffs, as stated above, it was a primary object to employ fast dyes since it was already known that disperse dyes could be employed. Therefore the dyestuffs falling within the scope of this invention are the anionic dyes. Certain anionic dyes were found to be more satisfactory than others and among these are the direct dyes, e.g., Direct Red 81 (Cl. 28160), 2:1 premetallized azo dyes, e.g., Acid Red 201 (01. 18761) and Acid Red 180 (CL 8736) and azo or anthraquinone acid dyes. Among the azo and anthraquinone acid dyes, the most preferred are the monosulfonated ones. Similarly, among the 2:1 premetallized dyes, the monosulfonated and monosulfonamides are most preferred.
Dyes such as monosulfonated azo Acid Yellow 29 (CI. 18900), monosulfonated azo Acid Red 4 (CI. 14710) and monosulfonated anthraquinone Acid Blue 27 (CI. 61530) gave excellent color yield and, in most cases, were totally exhausted after 60 minutes at 212 F. On the other hand, dyes such as Acid Orange 45 (CI. 22195) Acid Red 73 (CI. 27290), Acid Blue 113 (CI. 26360) and Direct Yellow 44 (CI. 29000) gave poorer color yield and were far from total exhaustion. The latter dyes all have more than one acidic groups, i.e. sulfonic or carboxylic acid group, however, by use of the carriers and conditions of the present invention, even these dyestuffs produced dyeings unattainable by the prior art.
Conventional anionic and nonionic wetting agents may be employed if desired. Anionic wetting agents are preferred.
The following specific embodiments are merely exemplary and are not limiting:
EXAMPLE 1 10 g. of Du Pont type 472 nylon fiber is immersed in a bath prepared as follows:
To 300 cc. water at F. is added 2.0 g. benzophenone (dissolved in a small amount of ethanol and emulsified with Tween 20) and 0.05 g. Irgalev PBF anionic wetting agent. The pH of the bath is adjusted to 3.0 with formic acid and 0.2 g. Erio Fast Blue GRL (Acid Blue 25; CI. 62055) is dissolved.
The fiber is immersed in the dyebath and the dyebath is heated at 2-3 F./min. to the boil, i.e., about 212 F. The fiber is boiled for about one hour, washed with water and dried to achieve a deep, bright blue level dyeing. Fastness to wet and light conditions were outstanding.
EXAMPLE 2 Proceeding substantially in the same manner as in Example 1, several organic chemicals were employed to determine their carrier effect. Several were found to give significant exhaustion and these are benzyl benzoate, phenyl benzoate, o-bromobenzoic acid, 2-chlorobenzoic acid, monobenzyl phthalate, o-anisaldehyde, benzoin, succinic acid, and toluic acid.
EXAMPLE 3 Proceeding as in Example 1 but employing 0.2 g. of Acid Yellow 29 CI. 18900 and 1.5 g. of a 1:1 by weight mixture of benzophenone-butyl benzoate emulsified with Tween 20 (polyoxyethylene sorbitan monooleate), an excellent bright yellow dyeing was achieved. Acid Red 4 (CI. 14710) and Acid Blue 27 (Cl. 61530) produced similar excellent results with, in most cases, total exhaustion in 60 minutes at 212 F. When employing dyes such as Acid Orange 45 (Cl. 22195), Acid Red 73 (CI. 27290), Acid Blue 113 (CI. 26360) and Direct Yellow 44 (CL 29000) (all of which contain more than one acidic group, e.g. carboxylic and sulfonic), exhaustion was decreased.
1. A process for the dyeing of linear high molecular weight silk-like polyamide fibers, wherein recurring polyamide linkages are an integral part of the polymer chain and at least 90% by weight of the repeating units of said polyamide are of the formula:
wherein R is the same or different member of the class consisting of hydrogen or methyl which comprises immersing said fiber in an aqueous dyebath containing (a) a carrier, benzophenone, in an amount effective to produce a level dyeing,
(b) an anionic dyestulf selected from the group consisting of azo and anthraquinone acid dyestuffs, 2:1 premetallized azo dyestuffs and direct dyestuffs,
the pH of said dyebath being in the range of 2 to 5 and the temperature of said dyeing being from about F. to about 212 F.
2. The process according to claim 1 wherein the pH is adjusted to between 3 and 5 with formic acid and the dyeing temperature is between about 200 F. and 212 F.
3. The process according to claim 2 wherein the carrier is employed at concentrations of between 10 and 25% by weight based on the fiber.
4. The process according to claim 3 wherein the acid dyestutf is a monosulfonated azo or monosulfonated anthraquinone.
5. The process according to claim 3 wherein the dyebath contains an anionic or non-ionic wetting agent.
6. The process of claim 1 wherein butyl benzoate is present in addition to the benzophenone.
OTHER REFERENCES Lynn: Advances in Textile Processing, vol. I, 1961,
pp. 360-363, pub. by Textile Book Pub. Inc., New York, N.Y.
DONALD LEVY, Primary Examiner